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1.
H. J. Carlisle T. G. Hales B. A. Schlinger 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1998,182(4):531-538
Songbirds are widely studied to investigate the hormonal control of behavior. However, little is known about the effects
of steroids on neurotransmission in these birds. We used electrophysiological and pharmacological techniques to characterize
γ-aminobutyric acid (GABA) type A receptors (GABAA) of primary cultured telencephalic and hippocampal neurons from developing zebra finches. Additionally, their modulation
by 17β-estradiol(E2), 5α- and 5β-dihydrotestosterone (DHT), 5α- and 5β-pregnan-3α-ol-20-one, and corticosterone was examined. Whole-cell GABA-evoked
currents were inhibited by picrotoxin (10 μmol l−1) and bicuculline methiodide (10 μmol l−1) and potentiated by pentobarbital (100 μmol l−1) and propofol (3 μmol l−1). Loreclezole (10 μmol l−1) potentiated GABA-evoked currents, suggesting the presence of β2, β3 and/or β4 subunits. Diazepam (1 μmol l−1) potentiated currents, while Zn2+ (1 μmol l−1) caused no inhibition, indicating the presence of γ subunits. 5α- and 5β-Pregnan-3α-ol-20-one (100 nmol l−1) potentiated currents, whereas E2 (1 μmol l−1), 5α- and 5β-DHT (1 μmol l−1), and corticosterone (10 μmol l−1) had no detectable effect. We conclude that zebra finch telencephalic and hippocampal GABAA receptors include α, β, and γ subunits and are similar to their mammalian counterparts in both their biophysical and pharmacological
properties. Additionally, GABA-evoked currents are greatly potentiated by 5α- and 5β-pregnan-3α-ol-20-one but show little
or no acute modulation by sex steroids or corticosterone.
Accepted: 12 November 1997 相似文献
2.
Spontaneous neuronal activity plays an important role in development. However, the mechanism that underlies the long-term spontaneous developmental change of cultured neuronal networks in vitro is not well understood. To investigate the contribution of inhibitory and excitatory connections to the development of neuronal networks, dissociated neurons from an embryonic rat hippocampal formation were cultured on a multi-electrode array plate and spontaneous activities were recorded by multi-channel system. These spontaneous activities were compared to bicuculline-induced firings, which were recorded by 60 electrodes simultaneously from 1 to 14 weeks in vitro (WIV). The phenomena showed that the spontaneous firing activities changed from an initial pattern of synchronized bursts to a later pattern of high frequency random spikes. The bicuculline-induced firing activities transformed from a pattern of synchronized bursts throughout all active sites in 3 WIV, to a pattern of local synchronized or random spikes appearing in the intervals of synchronized bursts after 11 WIV, while the firing rate hardly changed. Kynurenic acid, a broad-spectrum glutamate receptor antagonist, blocked all activities while CNQX inhibited only the local synchronized or random spikes. These suggest that the inhibitory connection was age-dependent degraded in vitro and the developmental spontaneous firing pattern was built by the homeostatic balance of the excitatory-inhibitory connection networks. Long-term cultures on MEA provided a useful tool to measure the relationship between spontaneous developmental change and pharmacological influence in vitro. 相似文献
3.
Various media and Ca2+ concentrations are employed to culture neural progenitor cells (NPCs). We have therefore explored the effects of extracellular calcium concentrations on the survival, proliferation, spontaneous apoptosis and self-renewal capacity of mesencephalic NPCs grown adherently and as free-floating neurospheres. We employed EMEM supplemented with various concentrations of extracellular CaCl2 (0.1–1 mM). Raising the calcium concentration from 0.1 mM to 0.6 mM resulted in an increased number of NPCs growing as a monolayer and increased the protein yield of cells growing in neurospheres (24±3 μg total proteins in 0.1 mM Ca2+ medium vs. 316±34 μg proteins in 1 mM Ca2+ medium). Concentrations more than 0.6 mM did not result in a further improvement of proliferation or survival. Elimination of calcium from our control medium by 1 mM EGTA resulted in a decrease in cell number from 82±2×104 NPCs/ml observed in control medium to 62±2×104 NPCs/ml observed in calcium-free media. Protein yield dropped significantly in calcium-free media, accompanied by the decreased expression of the proliferation marker PCNA and the pro-survival marker Bcl-2. Two weeks of expansion as neurospheres caused spontaneous cell death in more than 90% of NPCs grown in 0.1 mM CaCl2 EMEM compared with 42% in 1 mM CaCl2 EMEM. Although the action of Ca2+ on NPCs appears to be complex, the presented data strongly suggest that extracellular calcium plays a crucial role in the maintenance of NPCs in a healthy and proliferating state; physiological concentrations (>1.0 mM) are not required, a concentration of 0.5 mM being adequate for cell maintenance. 相似文献
4.
The effects of ethanol on neuronal network activity were studied in dissociated cultures of rat hippocampus. Exposure to low (0.25–0.5%) ethanol concentrations caused an increase in synchronized network spikes, and a decrease in the duration of individual spikes. Ethanol also caused an increase in rate of miniature spontaneous excitatory postsynaptic currents. Higher concentrations of ethanol eliminated network spikes. These effects were reversible upon wash. The effects of the high, but not the low ethanol were blocked by the GABA antagonist bicuculline. The enhancing action of low ethanol was blocked by apamin, an SK potassium channel antagonist, and mimicked by 1-EBIO, an SK channel opener. It is proposed that in cultured hippocampal networks low concentration of ethanol is associated with SK channel activity, rather than the GABAergic receptor. 相似文献
5.
The thermodynamic parameters enthalpy and entropy of the interaction between calcium(II) or copper(II) with 5′-UMP, 5′-CMP,
5′-AMP, 5′-GMP or 5′-IMP in aqueous solution were determined calorimetrically (ionic strength adjusted to 0.1 with tetramethylammonium
bromide) at 25 °C and pH 7 for Ca(II) or pH 3–5 for Cu(II). The experimental conditions were carefully selected to avoid polynuclear
complex formation and nucleotide self-stacking. The calorimetric data confirm the tendency toward macrochelation which was
indicated by Sigel after very precise potentiometric studies, and which follows the order Cu(II)>Ca(II) for the metal ions
and GMP>IMP>AMP>CMP=UMP for the nucleotides. Macrochelate formation for these metal-nucleoside monophosphate complexes is
energetically favorable and entropically unfavorable.
Received: 13 August 1999 / Accepted: 1 February 2000 相似文献
6.
Bestwick CS Ralton LD Milne L Kong Thoo Lin P Duthie SJ 《Cell biology and toxicology》2011,27(6):455-463
Bisnaphthalimido compounds bis-intercalate to DNA via the major groove and are potentially potent cancer therapeutics. Previously,
we incorporated natural polyamines as linkers connecting the two naphthalimido ring moieties to create a series of soluble
bisnaphthalimidopropyl polyamines (BNIPPs). Here, extending earlier work on bisnaphthalimidopropylspermidine (BNIPSpd)-induced
apoptosis in colon adenocarcinoma Caco-2 cells, we compare the cytotoxicity and genotoxicity of BNIPSpd relative to the spermine
and oxaspermine derivatives, bisnaphthalimidopropylspermine (BNIPSpm) and bisnaphthalimidopropyloxaspermine (BNIPOSpm). The
order of cytotoxicity after 24 h was BNIPSpd (IC50 = 0.47 μM) > BNIPSpm (IC50 = 10.04 μM) > BNIPOSpm (IC50 >50 μM). After a 72-h BNIPOSpm exposure, an IC50 = 10.25 μM was achieved. With 4-h exposure to BNIPSpd or BNIPSpm or 12-h exposure to BNIPOSpm, concentrations ≥1 μM induced
a significant dose-dependent increase in DNA damage as measured by alkaline single-cell gel electrophoresis. The longer incubation
times required for BNIPOSpm to induce DNA strand breaks reflect a slower rate of BNIPOSpm cellular distribution as monitored
via BNIPP fluorescence within the cells. Moreover, exposure to a non-genotoxic concentration of BNIPSpd, BNIPSpm (0.1 μM for
4 h) or BNIPOSpm (0.1 μM for 12 h) induced a significant decrease in repair of oxidative DNA damage induced by hydrogen peroxide.
In conclusion, BNIPP exposure in Caco-2 cells is associated with significant induction of DNA damage and inhibition of DNA
repair at non-genotoxic concentrations. The latter is a novel consequence of BNIPP–cell interactions which adds to the spectrum
of therapeutically relevant activities that may be exploited for the design and development of naphthalimide-based therapeutics. 相似文献
7.
Characteristics of non-specific permeability and H+-ATPase inhibition induced in the plasma membrane of Nitella flexilis by excessive Cu2+ 总被引:1,自引:0,他引:1
Effects of Cu2+ on a non-specific conductance and H+-ATPase activity in the plasma membrane of the freshwater alga Nitella flexilis L. Agardh was studied using a conventional microelectrode voltage-clamp technique. We show that a Cu2+-induced increase in the non-specific conductance is related to the formation of pores in the plasma membrane. Pore formation
is the result of unidentified chemical reactions, since the Q10 for the rate of increase of conductance over time was about 3. Various oxidants and antioxidants (10 mmol/l H2O2, 10 mmol/l ascorbate, 100 μg/ml superoxide dismutase, and 100 μg/ml catalase) did not alter Cu2+-induced changes in the plasma membrane conductance, suggesting that the effect of Cu2+ was unrelated to peroxidation of plasma-membrane lipids. In contrast, organic and inorganic Ca2+-channel antagonists (nifedipine, Zn2+, Cd2+, Fe2+, Ni2+) inhibited the Cu2+-induced non-specific conductance increase. This suggests that changes in Ca2+ influx underlie this effect of Cu2+. Decreasing the pH or the ionic strength of external solutions also inhibited the Cu2+-induced plasma-membrane conductance increase. Copper was also found to inhibit plasma-membrane H+-ATPase activity with half-maximal inhibition occurring at about 5–20 μmol/l and full inhibition at about 100–300 μmol/l.
The Hill coefficient of Cu2+ inhibition of the H+-ATPase was close to two.
Received: 8 December 1999 / Accepted: 16 August 2000 相似文献
8.
Summary. The neurotoxicity of domoic acid was studied in 2–3 week old rat hippocampal slice cultures, derived from 7 day old rat pups.
Domoic acid 0.1–100 μM was added to the culture medium for 48 hrs, alone or together with the glutamate receptor antagonists NS-102 (5-Nitro-6,7,8,9-tetrahydrobenzo[G]indole-2,3-dione-3-oxime),
NBQX (2,3-dihydroxy-6-nitro-7-sulphamoyl-benzo(F)quinoxaline) or MK-801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]-cyclohepten-5,10-imine
hydrogen maleate), followed by transfer of the cultures to normal medium for additional 48 hrs. Neuronal degeneration in the
fascia dentata (FD), CA3 and CA1 hippocampal subfields was monitored and EC50 values estimated by densitometric measurements of the cellular uptake of propidium iodide (PI). The CA1 region was most sensitive
to domoic acid, with an EC50 value of 6 μM domoic acid, estimated from the PI-uptake at 72 hrs. Protective effects of 10 μM NBQX against 3 and 10 μM domoic acid were observed for both dentate granule cells and CA1 and CA3c pyramidal cells. NS102 and MK 801 only displayed
protective effects when combined with NBQX. MK801 significantly increased the combined neuroprotective effect of NBQX and
NS102 against 10 μM domoic acid in both CA1 and FD, but not in CA3. We conclude, that domoic acid neurotoxicity in CA3 and in hippocampal slice
cultures in general primarily involves AMPA/kainate receptors. At high concentrations (10 μM domic acid) NMDA receptors are, however, also involved in the toxicity in CA1 and FD.
Received June 29, 2001 Accepted August 6, 2001 Published online June 3, 2002 相似文献
9.
The modulation of the calmodulin-induced inhibition of the calcium release channel (ryanodine receptor) by two sulfhydryl
oxidizing compounds, 4-(chloromercuri)phenyl–sulfonic acid (4-CMPS) and 4,4′-dithiodipyridine (4,4′-DTDP) was determined by
single channel current recordings with the purified and reconstituted calcium release channel from rabbit skeletal muscle
sarcoplasmic reticulum (HSR) and [3H]ryanodine binding to HSR vesicles. 0.1 μm CaM reduced the open probability (P
o
) of the calcium release channel at maximally activating calcium concentrations (50–100 μm) from 0.502 ± 0.02 to 0.137 ± 0.022 (n= 28), with no effect on unitary conductance. 4-CMPS (10–40 μm) and 4,4′-DTDP (0.1–0.3 mm) induced a concentration dependent increase in P
o (> 0.9) and caused the appearance of longer open states. CaM shifted the activation of the calcium release channel by 4-CMPS
or 4,4′-DTDP to higher concentrations in single channel recordings and [3H]ryanodine binding. 40 μm 4-CMPS induced a near maximal (P
o
> 0.9) and 0.3 mm 4,4′-DTDP a submaximal (P
o
= 0.74) channel opening in the presence of CaM, which was reversed by the specific sulfhydryl reducing agent DTT. Neither
4-CMPS nor 4,4′-DTDP affected Ca-[125I]calmodulin binding to HSR. 1 mm MgCl2 reduced P
o
from 0.53 to 0.075 and 20–40 μm 4-CMPS induced a near maximal channel activation (P
o
> 0.9). These results demonstrate that the inhibitory effect of CaM or magnesium in a physiological concentration is diminished
or abolished at high concentrations of 4-CMPS or 4,4′-DTDP through oxidation of activating sulfhydryls on cysteine residues
of the calcium release channel.
Received: 22 July 1999/Revised: 15 November 1999 相似文献
10.
Selenium concentrations in the blood of 112 (56 females and 56 males) normal subjects, from different regions of the Punjab
(Pakistan), have been determined using the technique of inductively coupled plasma-mass spectrometry. The whole blood selenium
concentrations were found to be 452 ± 12 ppb (parts per billion or nano-gram of Se per gram freeze-dried blood or 96 ± 3 μg/L
), with 470 ± 16 ppb (or 100 ± 4 μg/L) in female and 435 ± 16 ppb (or 92 ± 4 μg/L) in male population. Compared with other
populations of the world, these levels are amongst the lowest. 相似文献
11.
Hawkes WC Richter BD Alkan Z Souza EC Derricote M Mackey BE Bonnel EL 《Biological trace element research》2008,122(2):107-121
The essential nutrient selenium is required in microgram amounts [recommended dietary allowance (RDA) = 55 μg/day, 699 nmol/day]
and has a narrow margin of safety (upper tolerable intake limit = 400 μg/day, 5 μmol/day). We conducted a randomized placebo-controlled
study of high-selenium yeast, the form used in most supplements (300 μg/day, 3.8 μmol/day), administered to 42 free-living
healthy men for 48 weeks. Dietary intakes of selenium, macronutrients, and micronutrients were not different between groups
and did not change during the study. Supplementation more than doubled urinary selenium excretion from 69 to 160 μg/day (876
to 2,032 nmol/day). Urinary excretion was correlated with recent selenium intake estimated from 3-day diet records: urinary
selenium excretion = 42 μg/day (533 nmol/day) + 0.132 × dietary selenium intake, p < 0.001. Dietary selenium intake was not significantly correlated with the other indicators of selenium status, presumably
because urinary selenium excretion reflected recent intake, and tissue selenium was homeostatically controlled. After 48 weeks
of supplementation, plasma selenium was increased 60% from 142 to 228 μg/l (1.8 to 2.9 μmol/l), and erythrocyte selenium was
approximately doubled from 261 to 524 μg/l (3.3 to 6.6 μmol/l). Selenium concentrations increased more modestly in hair (56%)
and platelets (42%). Platelets were the only blood component in which glutathione peroxidase activity was significantly related
to selenium content. Selenium levels decreased rapidly after the end of supplementation, and there were no significant differences
in selenium status indicators between groups by week 96. The absorption, distribution, and excretion of selenium from high-Se
yeast were similar to selenium in foods. 相似文献
12.
Lead and catechol hematotoxicity in vitro using human and murine hematopoietic progenitor cells 总被引:1,自引:0,他引:1
In vitro cloning assays for hematopoietic myeloid and erythroid precursor cells have been used as screening systems to investigate
the hematotoxic potential of environmental chemicals in humans and mice. Granulocyte-monocyte progenitors (CFU-GM) from human
umbilical cord blood and from mouse bone marrow (Balb/c and B6C3F1) were cultured in the presence of lead and the benzene
metabolite catechol. Erythroid precursors (BFU-E) from human umbilical cord blood were cultured in the presence of lead. The
in vitro exposure of the human and murine cells resulted in a dose-dependent depression of the colony numbers. The concentration–effect
relationship was studied. Results showed that:
(1) Based on calculated IC50 values, human progenitors are more sensitive to lead and catechol than are murine progenitors.
The dose that caused a 50% decrease in colony formation after catechol exposure was 6 times higher for murine cells (IC50
= 24 μmol/L) than for human cord blood cells (IC50 = 4 μmol/L). Lead was 10–15 times more toxic to human hematopoietic cells
(IC50 = 61 μmol/L) than to murine bone marrow cells from both mice strains tested (Balb/c, IC50 = 1060 μmol/L; B6C3F1, IC50
= 536 μmol/L).
(2) A lineage specificity was observed after exposure to lead. Human erythroid progenitors (hBFU-E) (IC50 = 3.31 μmol/L) were
found to be 20 times more sensitive to the inhibitory effect of lead than were myeloid precursors (hCFU-GM) (IC50 = 63.58
μmol/L).
(3) Individual differences in the susceptibility to the harmful effect of lead were seen among cord blood samples.
(4) Toxicity of lead to progenitor cells occurred at environmentally relevant concentrations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
13.
It has been reported that piperine (PIP) and deoxyschizandrin (DS) can modulate synchronized Ca2+ oscillations in cultured hippocampal neuronal networks. We investigated the modulation effects of four different combinations of piperine and deoxyschizandrin on synchronized Ca2+ oscillations in cultured hippocampal neuronal networks. The results showed that all four combinations (PIP:DS 4.9:1.9, 2.45:2.85, 7.35:0.95, and 2.45:0.95 mg/L) inhibit Ca2+ oscillation intensity to a similar extent. However, the first three combinations had strong inhibitory effects on the frequency of Ca2+ oscillations whereas the last combination (2.45:0.95 mg/L) only slightly enhanced the frequency of Ca2+ oscillations. We propose an improved Chay’s model to explain the mechanism of the effects of piperine and deoxyschizandrin on synchronized Ca2+ oscillations in cultured hippocampal neuronal cells. We concluded that deoxyschizandrin modulated synchronized Ca2+ oscillations in cultured hippocampal neuronal networks bidirectionally and the effect depended on concentration. Deoxyschizandrin reduced voltage-gated sodium channel conductance and ATP-sensitive potassium channel conductance, and affected the rate of exchange of intracellular calcium and the pump activity of Ca2+-ATPase in the endoplasmic reticulum (ER). Piperine reduced the activity of calcium release in the ER, and reduced the pump activity of calcium in the cytomembrane or enhanced the pump activity of Ca2+-ATPase in the ER. 相似文献
14.
Akula Ramakrishna Parvatam Giridhar Gokare Aswathanarayana Ravishankar 《In vitro cellular & developmental biology. Plant》2011,47(6):667-673
High-frequency somatic embryogenesis was achieved in Coffea canephora using calcium ionophore A23187, which influences the influx of calcium into a cell. With 100 μM calcium ionophore and 5 mM
calcium, 85% and 70% of cultures produced embryogenic tissue, with 105 ± 7 and 95 ± 8 primary embryos from each callus mass
respectively. Medium supplemented with 100 μM EGTA (calcium chelator) or 1 mM verapamil (calcium channel blocker) significantly
reduced somatic embryogenesis. Calcium imaging studies were done to determine the relationship between morphogenetic response
and the cellular calcium levels. The calcium ionophore/calcium treatment was very effective in driving cellular machinery
toward embryogenesis. The embryos were regenerated into plantlets when cultured on MS medium supplemented with 5 mM calcium/100 μM
calcium ionophore A23187. Somatic embryogenesis-derived plants were successfully transferred to soil and grown to maturity
in the field. 相似文献
15.
Summary. We report that a novel substance named dictyopyrone C (DPC) has remarkable effects on growth and differentiation of Dictyostelium discoideum Ax-2 cells, in a dose-dependent manner. In the presence of 3–15 μM DPC, differentiation of starving Ax-2 (clone MS) cells
was greatly enhanced in submerged culture, when vegetative MS cells were harvested at the mid-late-exponential growth phase
(>3 × 106 cells per ml) and starved. In contrast, DPC above 30 μM markedly impaired the progression of differentiation including cell
aggregation, most of starved cells being round after 3–4 h of DPC application and then lysed during further incubation. In
the presence of 30 μM DPC however, MS cells that had been harvested at the early exponential growth phase (<5 × 105 cells per ml) and starved became neither round nor lysed and exhibited rather enhanced differentiation. Essentially the same
results were obtained in cultures of starved cells on nonnutrient agar. With respect to the DPC effect on MS cells growing
in axenic medium, cell lysis and growth inhibition by DPC at concentrations higher than 15 μM were realized in the mid-late-exponential-growth-phase
cells (>3 × 106 cells per ml) but not in the early-exponential-growth-phase cells (<5 × 105 cells per ml). Moreover, analysis using synchronized MS cells has demonstrated that the DPC effect changes in a cell-cycle-dependent
manner. In contrast to such unique DPC actions, the pyrone ring of DPC had no effects on growth and differentiation within
the range of 3–120 μM tested. These findings strongly suggested the importance of the combined structure of the pyrone ring
and the linear carbon chain in revelation of the DPC activities.
Received August 5, 2002; accepted November 11, 2002; published online April 8, 2003
RID="*"
ID="*" Correspondence and reprints: Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences,
Tohoku University, Aoba, Sendai 980-8578, Japan. E-mail: ymaeda@mail.cc.tohoku.ac.jp 相似文献
16.
Malaysia is the world’s leading producer of palm oil products that contribute US$ 7.5 billion in export revenues. Like any
other agro-based industries, it generates waste that could be utilized as a source of organic nutrients for microalgae culture.
Present investigation delves upon Isochrysis sp. culture in POME modified medium and its utilization as a supplement to Nanochloropsis sp. in rotifer cultures. The culture conditions were optimized using a 1 L photobioreactor (Temp: 23°C, illumination: 180 ∼ 200 μmol
photons m−2s−1, n = 6) and scaled up to 10 L outdoor system (Temp: 26–29°C, illumination: 50 ∼ 180 μmol photons m−2s−1, n = 3). Algal growth rate in photobioreactor (μ = 0.0363 h−1) was 55% higher compared to outdoor culture (μ = 0.0163 h−1), but biomass production was 1.3 times higher in outdoor culture (Outdoor = 91.7 mg m−2d−1; Photobioreactor = 69 mg m−2d−1). Outdoor culture produced 18% higher lipid; while total fatty acids (FA) was not significantly affected by the change in
culture systems as both cultures yield almost similar concentrations of fatty acids per gram of sample (photobioreactor = 119.17 mg
g−1; outdoor culture = 104.50 mg g−1); however, outdoor cultured Isochrysis sp. had 26% more polyunsaturated fatty acids (PUFAs). Rotifers cultured in Isochrysis sp./ Nanochloropsis sp. (1:1, v/v) mixture gave similar growth rate as 100% Nanochoropsis sp. culture (μ = 0.40 d−1), but had 45% higher counts of rotifers with eggs (t = 7, maximum). The Isochrysis sp. culture successfully lowered the nitrate (46%) and orthophosphate (83%) during outdoor culture. 相似文献
17.
Seema Jain Priyamvada Sharma Shobha Kulshreshtha Govind Mohan Saroj Singh 《Biological trace element research》2010,133(2):162-170
Pre-eclampsia is the most common medical complication of pregnancy associated with increased maternal and infant mortality
and morbidity. Its exact etiology is not known, although several evidences indicate that various elements might play an important
role in pre-eclampsia. This study was carried out to analyze and to compare the concentration of calcium, magnesium, and zinc
in the serum of women with pre-eclampsia and in normal pregnant women. Fifty clinically diagnosed patients with pre-eclampsia
(25 with mild and 25 with severe pre-eclampsia) and 50 normal pregnant controls were enrolled in this study. The serum calcium,
magnesium, and zinc levels were estimated with an atomic absorption spectrophotometer. The mean serum levels of calcium, magnesium,
and zinc in normal pregnant group were 2.45 ± 0.18 mmol/L, 0.79 ± 0.13 mmol/L, and 15.64 ± 2.4 μmol/L, respectively, while
in mild pre-eclamptic group, these were 2.12 ± 0.15 mmol/L, 0.67 ± 0.14 mmol/L, and 12.72 ± 1.7 μmol/L, respectively. Serum
levels in severe pre-eclamptic group were 1.94 ± 0.09 mmol/L, 0.62 ± 0.11 mmol/L, and 12.04 ± 1.4 μmol/L, respectively. These
results indicate that reduction in serum levels of calcium, magnesium, and zinc during pregnancy might be possible contributors
in etiology of pre-eclampsia, and supplementation of these elements to diet may be of value to prevent pre-eclampsia. 相似文献
18.
Trion A Schutte-Bart C Bax WH Jukema JW van der Laarse A 《Molecular and cellular biochemistry》2008,308(1-2):25-33
Background Vascular calcification is an organized process in which vascular smooth muscle cells (VSMCs) are implicated primarily. The
purpose of the present study was to assess the effects of calcium antagonists and statins on VSMC calcification in vitro.
Methods VSMC calcification was stimulated by incubation in growth medium supplemented with 10 mmol/l β-glycerophosphate, 8 mmol/l
CaCl2, 10 mmol/l sodium pyruvate, 1 μmol/l insulin, 50 μg/ml ascorbic acid, and 100 nmol/l dexamethasone (calcification medium).
Calcification, proliferation, and apoptosis of VSMCs were quantified. Results Calcium deposition was stimulated dose-dependently by β-glycerophosphate, CaCl2, and ascorbic acid (all P < 0.01). Addition of amlodipine (0.01–1 μmol/l) to the calcification medium did not affect VSMC calcification. However, atorvastatin
(2–50 μmol/l) stimulated calcium deposition dose-dependently. Combining treatments stimulated calcification to a degree similar
to that observed with atorvastatin alone. Both atorvastatin and amlodipine inhibited VSMC proliferation at the highest concentration
used. Only atorvastatin (50 μmol/l) induced considerable apoptosis of VSMCs. Conclusion In vitro calcification of VSMCs is not affected by amlodipine, but is stimulated by atorvastatin at concentrations ≥10 μmol/l,
which could contribute to the plaque-stabilizing effect reported for statins.
J. W. Jukema is an Established Clinical Investigator of The Netherlands Heart Foundation 2001D032. 相似文献
19.
Filipendula ulmaria (L.) Maxim (meadowsweet) is a medicinal plant that is claimed to have several biological activities, including anti-tumor,
anti-carcinogenic, anti-oxidant, anti-coagulant, anti-ulcerogenic, anti-microbial, anti-arthritic, and immunomodulatory properties.
This report describes, for the first time, an efficient plant regeneration system for F. ulmaria via adventitious shoot development from leaf, petiole, and root explants cultured on Murashige and Skoog’s minimal organics
medium containing different concentrations of thidiazuron (TDZ), benzyladenine, and kinetin either alone or in combination
with different auxins. Relatively extensive/prolific shoot regeneration was observed in all three explant types with TDZ in
combination with indole-3-acetic acid (IAA). Gibberellic acid (GA3), TDZ, and IAA combinations were also tested. The best shoot proliferation was observed among root explants cultured on media
supplemented with 0.45 μM TDZ + 2.85 μM IAA + 1.44 μM GA3. Regenerated shoots were transferred to rooting media containing different concentrations of either IAA, indole-3-butyric
acid (IBA), naphthalene acetic acid, or 2,4-dichlorophenoxyacetic acid. Most shoots developed roots on medium with 2.46 μM
IBA. Rooted explants were transferred to vermiculite in Magenta containers for a 2-wk acclimatization period and then finally
to plastic pots containing potting soil. The plantlets in soil were kept in growth chambers for 2 wk before transferring to
greenhouse conditions. 相似文献
20.
Summary Solution calcium concentrations required for the growth of a range of plant species, including both monocotyledons and dicotyledons,
were determined in two experiments in which plants were grown in flowing solution culture at constantly maintained calcium
concentrations ranging from 0.5 to 3000 μM. Calcium chloride was used as the calcium source in the first experiment, calcium sulphate was used in the second.
At calcium concentrations of 10 μM and below, all species developed calcium deficiency symptoms. The severity of the deficiency was more pronounced in the dicotyledons
than in the monocotyledons. However, cassava was much more tolerant than all other dicotyledons and equally as tolerant as
rice, the most tolerant monocotyledon.
Solution calcium concentrations required for 90% of maximum yield were generally lower for monocotyledons (3 to 20 μM) than for dicotyledons (7 to 720μM) when calcium chloride was used as the calcium source. When calcium sulphate was used, 7 out of 11 species, including 3 monocotyledons,
required external calcium concentrations of 1200 μM and above. The results are discussed in relation to effects of solution composition and the choice of counter-ions on plant
response to calcium and other macronutrient cations. It is concluded that yield depressions due to toxicity of excesses of
chloride, and possibly other counter-ions, can lead to serious underestimation of limiting external cation concentrations
for plant growth. 相似文献